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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?DC7kt6+dRyqswcIyb546ulU/2GD55aMi/fxGxKVr0yfhWm5F7PZ5tLz0fae7?= =?us-ascii?Q?BFQx8kjCMvRTSU6C1rztmILuLbfYAk14KDuEfnN9kYOF4wrLYVVilrvek7bA?= =?us-ascii?Q?fqiXPgQasrSzlwZQwrpPgMWPdR5bG5HW1g9yhauPi2DqJNzvWhwZkK3szXKT?= =?us-ascii?Q?RpTxS8UUNWcw4bvB+E0aq1Z22dIwt7tS3NfYFReJ0E3WZmCk2jCiu/BrLcji?= =?us-ascii?Q?8aIOrn/lZo0LbiiZ6anAD7JE2GDyOVkFqSTGeWGIMw+2lYPXYqSZDLIRAfyo?= =?us-ascii?Q?6vyGSrgqB/sBtMBs0F2RmuP3tzrgNkHLrYXfVMaQLqfYoLhd1V9LXGx+6Tny?= =?us-ascii?Q?5PutkcUxRIURuY5/+sPCDdcqjUMDEZ55qmdeaBy7RP13b794mP1ZDLwq7MNp?= =?us-ascii?Q?Pl0acAS3oyUixclGQu2Ib/BST/H9sTwLgLs9Uq6CNjfq//2x6eLUZtpscO2x?= =?us-ascii?Q?PtVk1VUxgO75IRS2lCyV4JXAdQCiBzC8pHQc9CGytTnFnDqJGpoEWpKkEhwS?= =?us-ascii?Q?+vHQGPyhrQvJkBmjDAc7Z7YXkyOZBRqBDeVzAZGouX//ZxgzN1PPIUtbPbAw?= =?us-ascii?Q?OLD2gpcWfbLSTsPDLvyZ0FfiIxWTWoFL28kyS6sDg1EuQbMBnwWP8i3y+P5B?= =?us-ascii?Q?R09boFQ2+cCMozEdOHQ8yyU4nKWQbtErKAf3CsrUzGKBtSUSr6RdzBDhqxNA?= =?us-ascii?Q?YDbBGgtPbEpk3ruwqhxYz0kUOO/7PuD9X5vErc2siexydWWz5qL/2yPQ9RvB?= =?us-ascii?Q?jU2sjSWmKef6jbex7s4XPt0Oawr2uwv4qn5QOwSz68AVw+4rbKKrq/l6p8QA?= =?us-ascii?Q?6YU9HvVWAt2yKilf8GiNeXsWW5MVjXWrJRghpoySbIOUqNcyuImrzWgLv35H?= =?us-ascii?Q?EyLgdNMpoqIOqNLvdLWtRJkn5y8JciV+5BL3qBAPl+FJGxNI5GK7RXLXUjTy?= =?us-ascii?Q?E3CK0/z3EEz7sBNBa5Kt053lQhda47HC1s8DgfC6uKk/+QT+q6VA4MwY3V8r?= =?us-ascii?Q?8e/KDp3l0oUibIeIUCtYXCqjTtKYyGmRri2feoOzghxvg16GPonGwQT8Y4Se?= =?us-ascii?Q?xfgNblxgbirGUFKh1Lt/91u7tg7z5MKltmMyXAHQAuOSBitSWuurRbIWB+1F?= =?us-ascii?Q?8cr/DTBV/7z3I1GrN+MdnhlmMUNfoMOy8X6Se8PcO2zwGHNIjy95MB4ribtv?= =?us-ascii?Q?sBWVQJ7wClTPufkYPiwYH8zenPRfhbzMaBequOJ8uw6F8AeydWvklwlmE0QE?= =?us-ascii?Q?4aXocG/KZQv1UlaVO7xn7QVwEll2NDEJ9FQq3M5SHGFEnamzdTjGjvj2M1z/?= =?us-ascii?Q?eKkvsIMaE/9zHXZB2Dj6Y5EzWz3DlQHhmzzzDkTvQ9bxsny7S7lt8swq9maQ?= =?us-ascii?Q?HUmBMP4S0yYkP33eczND9jeCHXD5k/A38O6IS+XI+/oyLjrTWASorkqzugFT?= =?us-ascii?Q?e2nJkFVpljuSst39+hPJ2gntjD//Guv2mUTJ484HLdpG3wVaf9VMDlcR3Dv/?= =?us-ascii?Q?RXgL9M4BFJrmliCFBhXvPfd5MSFL1l8Hbqo467UeMhYLyjhxUCH1CFneVdVE?= =?us-ascii?Q?jP79w/qkxURNDp3NufVhKHD94fR2/RIbfzb+YgWSdRLiVV0BNzrNqEKVlno+?= =?us-ascii?Q?JkXdp/3/yQmwNUFtIC04WFRJPaCQ2FCB+ExDkEUuFnpmk26DqysMEPfLQ3Us?= =?us-ascii?Q?9DnqScX5uVVFbAI/pdpHIFsLmTXrNvJDoOCfLljA6iBcTvaS?= X-OriginatorOrg: atomlin.com X-MS-Exchange-CrossTenant-Network-Message-Id: d03913aa-d06f-4751-8208-08df02b32a38 X-MS-Exchange-CrossTenant-AuthSource: CWLP123MB6607.GBRP123.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Aug 2026 14:14:24.2976 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: e6a32402-7d7b-4830-9a2b-76945bbbcb57 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: d8+9vU9GFGAjlTEnK0BS/0bRx97SjZmbSOiUfrO7AiO/5AQImuDQbDUaQ8rOQHogYcr52CWTwwD0MrCVBGTudQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CWYP123MB8971 Currently, accessing scheduler debugging details for a specific CPU requires reading /sys/kernel/debug/sched/debug, which outputs information for all online CPUs. When investigating a latency anomaly or scheduling issue isolated to a specific CPU, accessing /sys/kernel/debug/sched/cpu/cpu/debug provides an immediate, targeted view of that runqueue. Add support for per-CPU debug files under: /sys/kernel/debug/sched/cpu/cpu/debug. Reading /sys/kernel/debug/sched/cpu/cpu/debug calls print_cpu() specifically for CPU , exposing CPU-specific runqueue details on demand. If the target CPU is currently offline, reading its file returns -ENODEV. Signed-off-by: Aaron Tomlin --- kernel/sched/debug.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 8793059688d7..a3f5b105b7ea 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -345,6 +345,7 @@ static const struct file_operations sched_verbose_fops = { }; static const struct seq_operations sched_debug_sops; +static void print_cpu(struct seq_file *m, int cpu); static int sched_debug_open(struct inode *inode, struct file *filp) { @@ -622,6 +623,47 @@ static void debugfs_fair_server_init(void) } } +static int sched_debug_cpu_show(struct seq_file *m, void *v) +{ + unsigned long cpu = (unsigned long) m->private; + + if (!cpu_online(cpu)) + return -ENODEV; + + print_cpu(m, cpu); + return 0; +} + +static int sched_debug_cpu_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, sched_debug_cpu_show, inode->i_private); +} + +static const struct file_operations sched_debug_cpu_fops = { + .open = sched_debug_cpu_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static __init void debugfs_cpu_init(void) +{ + struct dentry *d_cpu_dir; + unsigned long cpu; + char buf[16]; + + d_cpu_dir = debugfs_create_dir("cpu", debugfs_sched); + + for_each_possible_cpu(cpu) { + struct dentry *d_cpu; + + snprintf(buf, sizeof(buf), "cpu%lu", cpu); + d_cpu = debugfs_create_dir(buf, d_cpu_dir); + + debugfs_create_file("debug", 0444, d_cpu, (void *) cpu, &sched_debug_cpu_fops); + } +} + static __init int sched_init_debug(void) { struct dentry __maybe_unused *numa, *llc; @@ -679,6 +721,7 @@ static __init int sched_init_debug(void) #ifdef CONFIG_SCHED_CLASS_EXT debugfs_ext_server_init(); #endif + debugfs_cpu_init(); return 0; } -- 2.55.0